Sonographic assessment of the optic nerve sheath in idiopathic intracranial hypertension
ABSTRACT The aim of this work was to investigate the potential of ultrasound-based optic nerve sheath diameter (ONSD) measurements in detecting raised intracranial pressure in patients with idiopathic intracranial hypertension (IIH) and to describe ONSD response to lumbar puncture. In ten patients with newly diagnosed IIH, transorbital sonography was carried out to assess ONSD, OND (optic nerve diameter), and optic disc elevation before and after lumbar puncture. Twenty-five patients with other neurological disorders served as controls. Subjects with IIH showed a significantly enlarged ONSD on both sides (6.4 ± 0.6 mm vs. 5.4 ± 0.5 mm in controls; p < 0.001). The best cut-off value of ONSD for detecting raised ICP was 5.8 mm with a sensitivity of 90% and a specificity of 84%. After lumbar puncture, ONSD decreased bilaterally (right 5.8 ± 0.7 mm, p < 0.004; left 5.9 ± 0.7 mm, p < 0.043). No post-puncture changes could be observed with regard to OND and optic disc elevation. Sonographic ONSD evaluation may be useful as an additional tool to identify patients with raised intracranial pressure, as in IIH. Furthermore, our data suggest a potential usefulness of this method for monitoring of treatment effects. The degree of ONSD response to lumbar puncture differs in subjects with IIH, which may possibly be related to findings of a defective CSF circulation in the optic nerve sheath in this disorder, a state that is referred to as optic nerve compartment syndrome.
SourceAvailable from: Michael S Cartwright[Show abstract] [Hide abstract]
ABSTRACT: Ultrasound of cranial nerves is a novel subdomain of neuromuscular ultrasound (NMUS) which may provide additional value in the assessment of cranial nerves in different neuromuscular disorders. Whilst NMUS of peripheral nerves has been studied, NMUS of cranial nerves is considered in its initial stage of research, thus, there is a need to summarize the research results achieved to date. Detailed scanning protocols, which assist in mastery of the techniques, are briefly mentioned in the few reference textbooks available in the field. This review article focuses on ultrasound scanning techniques of the 4 accessible cranial nerves: optic, facial, vagus and spinal accessory nerves. The relevant literatures and potential future applications are discussed.Journal of Clinical Neurology 04/2015; 11(2):109-21. DOI:10.3988/jcn.2015.11.2.109 · 1.81 Impact Factor
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ABSTRACT: Two ultrasound tests that can be used to assess increased intracranial pressure (ICP) at the bedside are described. In outpatients receiving lumbar puncture and in intensive care patients with invasive ICP monitoring, we measured the optic nerve sheath diameter (ONSD) with transbulbar B-mode sonography and septum pellucidum undulation (SPU) induced by repeated passive head rotation with transtemporal M-mode sonography. We assessed the sensitivity and specificity of ONSD and SPU in the prediction of ICP >20 cm H2O. For ONSD, sensitivity was 53% and specificity 100% (n = 35, p < 0.001). The sensitivity of the SPU test was 75% and the specificity 100% (n = 32, p < 0.001). Although the SPU test may not feasible in some patients, it has high sensitivity and specificity comparable to those of ONSD measurement. The SPU test and ONSD may be useful alternatives to fundoscopy in clinical routine, preferably in combination.Ultrasound in Medicine & Biology 01/2015; 41(5). DOI:10.1016/j.ultrasmedbio.2014.12.023 · 2.10 Impact Factor
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ABSTRACT: B-mode sonography of the optic nerve is a promising new technique in the field of neurology. It may serve as an additional diagnostic tool in different diseases with altered intracranial pressure. The aim of this article is to give an overview on this technique and on its possible clinical applications.09/2012; 1(1-12):404-407. DOI:10.1016/j.permed.2012.01.001